Improvement in universal mandrels



\ in exact `central positions.

UNITED STATE s PATENT.. OEEIcE.

JAMEsGALLATN, JE., 'or NEW vonk, N. Y.-

Specification forming part of Letters Patent No. 1l2,580, dated March 14, 1871.

of Ithe city, county, and State of NewYork,

` have invented a new and Improved Universal Mandrel for Lathes and I do hereby declare that the following is a full, clear, and exact descriptionthereof, which will enable others skilled in the art to make and use the same, reference being 1 had to the accompanying drawing, forming part of .this specication, in which- Figure "l represents a vertical longitudinal section of my universal mandrel. Fig. 2 is a vertical transverse section Aof the same, taken on the planeof the line x w, Fig. 1. l

Similar letters of reference indicate corresponding parts.

The object of this invention is to provide a .universal mandrel which can be placed into lathes to `retain different-sized tubular articles Heretofore, vfor every diEerent-bored article a different-sized mandrel was required. To prevent this I arrange two cones upon a mandrel and make at least one of them longitudinally adjustable, so

Athat all articles whose bore is larger than the diameter of the mandrel'can be held in place H by the small ends of-the cones, which are forced into the ends of "such tube and then clamped.` The cones will serve to exactly cenwhich is centered and held in the lathe. Upon the mandrel are .fitted two hollow cones, B C, set with their small ends toward each other,

and prevented from revolving on the mandrel by groove and feather a, or other equivalent means. One cone, Bj, is securely liXed to the mandrel by a nut, I), which is tted upon the split shank c of B. The other cone, O, can be forced toward the cone B by a nut, d, screwed upon the mandrel.

The article E to be held and centered is slipped upon the mandrel when the cone B is olf, and is held against the end of the cone C. The cone B is then put on and locked fast. The nut D is nally turned to force the cone C forward, and to cause thereby the two cones to lock the tube E.

All diferentsized articles can by this arrangement be held and properly centered on the mandrel. v

I am aware that cones have already been used to clamp and hold hollow articles on differentimachines, and I do not claim their use per se, my invention consisting in the construction of a universal mandrel for lathes, whereby the necessity of using a separate mandrel for the varioussized tubes is dispensed with.

Having thus described my invention, I claim as new andv desire to secure by Letters Patent- As my improvement in universal mandrels of the species herein described, the split, tapered, and screw-threaded extremity c of the cone B, jointly with the nut b.

. JAMES GALLATIN, JE. Witnesses:

GEO. W. MABEE, ALEX. F. ROBERTS. 

